This invention relates to apparatus for measuring and displaying the rate of deceleration of a vehicle for the benefit of the operator in the following vehicle.
The premise of the invention is that a driver needs better information about the motion of the car in front of him, especially if it is slowing down, and that brake lights do not tell him enough.
The driver following needs to know how quickly the car in front is slowing down. A lit brake light only means that the front driver has his foot on the brake; the driver behind does not know if the front car is decelerating mildly or whether it is coming to an urgent stop. The lit brake light looks the same in either case.
With automobiles traveling at high speeds and with spacing acknowledged to be unsafe but a fact of life due to crowded and congested highways, this ambiguity in brake lights can and sometimes does cause rear end collisions with consequent vehicular damage, human injury, loss of life, and further road congestion.
To deal with this problem a variety of designs have been offered in which additional brake lighting or other signaling is produced to indicate the so-called panic stop or that hard braking is occurring. These are shown in U.S. Pat. Nos. 3,760,353, 3,501,742, and 4,170,723. U.S. Pat. Nos. 3,813,542, 4,686,503, and 4,730,181 provide for signaling before actual braking takes place, while U.S. Pat. No. 4,594,574 teaches the use of separate lights to indicate braking when the vehicle is in motion.
None of the preceding patents teaches the present invention.